Silicon is the dominant semiconductor for photolithographically fabricated electronics. Modern computing and telecommunications devices comprise large blocks of integrated circuits including large cache memories, large register files, and large instruction decoding units. Clock signals and data drivers often talk to a large number of on-chip circuits as well as chip-to-chip circuits. Also, propagation delay for on-chip and chip-to-chip components is increasing with higher densities and smaller feature dimensions. Since the speed of light is faster than the flow of electrons in conductive interconnects, there is a growing desire to integrate optoelectronics into systems for telecommunications and computer interconnections.
Increasing use is being made of integrated optoelectronics to convert electrical signals from integrated circuits into optical signals for transmission. An optical signal may travel over a waveguide or in free space to a detector which converts it back into an electrical signal. Information may be encoded into these optical signals through modulators which may modulate the amplitude or the frequency of the optical signal. However, the total propagation delay from an integrated circuit across the optoelectronics includes the delay through a detector and a modulator. Therefore, efficient detectors and modulators with low propagation delay are desirable for the continued success of very large scale integrated circuits, chip-to-chip and board-to-board interconnections.